Surface treated doctor blade

ABSTRACT

Disclosed is a surface treated doctor blade in which the surface of at least the blade edge portion thereof consists of a surface treatment coating film composed of a first layer consisting of a specific nickel-based plating and a second layer provided thereon which has low surface energy, and in which preferably at least a part of the blade edge end portion of the blade base material is exposed. In the surface treated doctor blade of the present invention, it is possible to improve wear resistance of the blade edge end and to suppress generation of printing failures during continuous printing. Further, in the mode in which at least a part of the blade base material is exposed, it is possible to reduce running-in time for adjustment of contact of the blade edge with the cylinder after replacement of the doctor blade.

TECHNICAL FIELD

The present invention relates to a doctor blade having on its surface adouble-layered coating film. More specifically, the present inventionrelates to a surface treated doctor blade which is superior insuppressing a printing failure attributable to the doctor blade that iscaused during continuous printing.

BACKGROUND ART

As shown in FIG. 1 and FIG. 2 (which is a partial enlarged view of FIG.1; it is to be noted that in both FIGS. 1 and 2, the blade portion is,for ease of understanding, depicted extremely large as compared with thecylinder), in gravure (intaglio) printing, a cylinder (1) having on itsperipheral surface a large number of minute recesses (not shown) calledcells corresponding to an image is used. A doctor blade (2) formed ofsteel or stainless steel is pressed against the peripheral surface ofthis cylinder with a fixed pressure, thereby scraping off ink (3)adhering to a non-image portion of the plate surface. This doctor bladeserves to completely remove the ink of the non-image portion and toleave a predetermined amount of ink on the image portion, so that thecontact pressure of the cylinder and the doctor blade has to be alwaysmaintained at a fixed level, and the edge part of the blade is requiredto have wear resistance. Thus, a doctor blade which has undergonesurface treatment such as plating (4) is generally used.

For example, there are proposed: (1) in JP 4-296556 A, a doctor bladewhose edge portion has a surface formed of an ink-repellent material(metal plating containing polymer particles);

(2) in JP 2001-80230 A, a backing-of-a-spatula preventing doctor bladewhose surface has undergone fluorine-containing treatment (e.g., a metalplating of eutectoid 4-fluorinated ethylene resin particles);

(3) in JP 2000-507523 A, a doctor blade whose surface is coated with apolymer having a poor surface energy of 10 to 60 mN/m; and

(4) in JP 3-64595 A, a surface treated doctor blade consisting of afirst layer of a nickel-based alloy and an upper layer of a chromiumplating and superior in rust resistance and wear resistance.

(5) In JP 2952333 B, there is proposed a method of manufacturing adoctor blade having a double-layered plating consisting of a first layerof Ni plating and an upper layer of Ni plating containing ceramicpowder.

(6) In JP 2001-1664 A, there is proposed a doctor blade in which thesurface of the blade core metal is coated with a primer plating coatingfilm and a diamond-like carbon coating film formed thereon, the primerplating being harder than the core metal and softer than thediamond-like carbon coating film.

However, these prior-art techniques have the following problems:

In the technique as proposed in (1), the surface of the blade edge isink repellent, and doctoring is performed without extracting the inkfrom the cells of the plate, whereby it is possible to fill the cellswith ink in a satisfactory manner, and even in precision printing, theconfigurations of the pixels can be reproduced in a satisfactory manner.However, since the surface treatment is effected with a single layer ofmetal containing ink repellent polymer particles, the wear resistance isinsufficient, and as continuous printing is conducted, the wear of theblade edge progresses rapidly, so that it is necessary to frequentlyreplace the blade, resulting in reduction in printing efficiency.

In the technique as proposed in (2), coating is effected on a bladesolely by metal plating in a single layer containing 4-fluorinatedethylene resin particles, whereby it is possible to effectively preventa printing failure called “backing of a spatula”, in which duringcontinuous printing, coating liquid is accumulated and grows on the backside of the blade edge (back side with respect to the direction to whichthe cylinder rotates (R side in FIG. 2)), and the accumulated liquiddrops are irregularly transferred to the original form to swell in dotsor streaks. However, with the metal plating using eutectoid4-fluorinated ethylene resin particles alone, it is impossible to obtaina sufficient degree of wear resistance since the plating is relativelysoft, and the wear of the blade edge progresses rapidly with continuousprinting, so that it is necessary to frequently replace the blade,resulting in a deterioration in printing efficiency. Further, with thissingle layer plating alone, a failure in scraping ink off the cylinderis likely to occur, and a printing failure (fog or the like) assumed tobe attributable to the scraping failure occurs in a relatively earlystage of continuous printing.

In the technique as proposed in (3), the blade surface is coated with apolymer with a poor surface energy to thereby prevent ink deposit when ahigh viscosity ink is used. However, since the substance with which theblade is coated is a polymer, the wear resistance of the blade is notimproved at all, and it is necessary to frequently replace the blade asa result of the wear of the blade edge, resulting in a low productionefficiency. Further, a failure in scraping chemical liquid off thecylinder is likely to occur, and a printing failure (fog or the like)occurs at a relatively early stage of printing.

In the techniques as proposed in (4) and (5), double-layered plating iseffected to thereby enhance adhesion of the upper plating layer, and thewear resistance of the blade edge is improved by chromium platingforming the outermost layer or ceramic-containing-nickel plating.Although the techniques are effective in mitigating the wear of theblade, since the plating coating film forming the outermost layer ishard, there is a problem in that a printing failure due to accelerationof the wear of the cylinder itself, damage of the cylinder, peeling ofthe plating coating film or the like is likely to occur.

In the technique as proposed in (6), two-layer treatment is adoptedusing a ceramic composite nickel coating film and a diamond-like carboncoating film, thereby preventing plate fog due to a failure in scrapingink off when using aqueous ink. However, this technique has a problem inthat adhesion between the diamond-like carbon coating film and theceramic composite nickel coating film is insufficient. As the blade edgeend is worn during continuous printing, the upper layer is likely to bepeeled, and the resultant peeled powder is mixed with the ink, so thatprinting failure is likely to occur. Further, there is a problem in thatthe production efficiency when providing the diamond-like carbon coatingfilm is rather low, and the provision requires a special apparatus suchas a plasma deposition apparatus, with the result that a production costitself is high, or the like.

Further, it has recently become more difficult to meet the user needsfor accuracy. There is a requirement for a more accurate reproducibilityfor image configuration, and minute image defects such as bleeding andblurring which were overlooked in the past matter much more nowadays.This problem cannot be solved by the prior-art techniques.

It is accordingly an object of the present invention to provide asurface treated doctor blade which solves the above problems in theprior art and which helps to improve the wear resistance of the bladeedge end and suppresses occurrence of printing failure during continuousprinting.

On the other hand, in the doctor blades according to the prior-arttechniques (1) to (6), the blade edge end is completely covered withplating (like the embodiment of the present invention as shown by FIG.3(c)). Thus, when printing is performed immediately after replacing theblade with a new blade, a printing failure such as streaking or fog isgenerated due to defective contact between the cylinder and the bladeedge end. In view of this, it is general practice to conduct arunning-in for 30 to 60 minutes in order for the blade to obtain a goodfit with the cylinder (conformability) which the blade contacts with,and then perform actual printing. As a result, there are problems inthat a time loss corresponding to the running-in is involved, whichmeans a very poor printing efficiency, and moreover, the cylinder can bedamaged during the running-in, or partial wear can occur on the blade(hereinafter, such problems will be collectively referred to as“conformability of the blade”).

Thus, another object of the present invention is to provide a surfacetreated doctor blade improved in conformability between cylinder andblade edge end to thereby reduce running-in time, superior in wearresistance of the blade edge end, which can suppress occurrence ofprinting failure during continuous printing.

DISCLOSURE OF THE INVENTION

After examining causes of printing failure during continuous printing,the present inventors have found out the following facts.

It is to be assumed that printing failures in the form of bleeding,blurring, fogging, etc. of the image generated between the early stageand the middle stage of continuous printing are mainly attributable to afailure in scraping ink off by the blade. To overcome this, thefollowing measures (1) and (2) have been found to be effective.

(1) To reduce the surface energy of the outermost treated blade surfaceat least on the front side (the front side with respect to the directionto which the cylinder rotates) of the blade edge end in contact with theink. It is to be assumed that by reducing the surface energy, thesurplus ink scraped off the non-image portion does not stay due to theink repellency of the coating film, and is efficiently discharged fromthe system through the contact area between cylinder and blade (portiona in FIG. 2), with the result that engulfing of ink into the innerportion (failure in scraping off of ink by the blade) is restrained.

(2) To set the surface hardness of the blade after treatment within aspecific range. It is to be assumed that by setting plating hardnesswithin a specific range, it is possible for the blade to apply a stable,uniform, and sufficient pressure onto the cylinder, thereby improvingthe ink scraping performance.

Further, the printing failure generated at the late stage of continuousprinting is mainly attributable to wear of the blade edge end, missingplating, damage and wear of the cylinder. It has been found out thatthese can be effectively restrained by the following measures:

(3) To reduce coefficient of friction of the blade surface, that is, toenhance lubricity of the surface and restrain cohesion wear at the pointof contact between the blade and the cylinder;

(4) To set surface hardness within a specific range; and

(5) To set film thickness within a specific range.

As stated above, to obtain a satisfactory printing performance forcontinuous printing, it is necessary for the doctor blade to satisfy allof the above (1) to (5) at the same time. With the prior-art techniques,it is difficult to satisfy all the above conditions. It has been foundout that this becomes possible only by adopting the double-layeredplating structure as proposed in the present invention and allottingdifferent functions to each plating layer.

Further, the present inventors conducted studies on conformability ofthe blade edge end, and have found out the following facts.

(6) To improve conformability of the blade edge end, it is effective toreduce hardness of the blade edge end portion (5 in FIG. 3), which isthe first part of the blade to come into contact with the cylinder. Itis not definitely known why this improves the conformability of theblade edge end. However, it is to be assumed that by reducing thehardness, deformation of the blade edge end when being pressed on thecylinder is encouraged, and as a result, the area of the blade portioncoming into contact with the cylinder increases, which contributes toimprovement in conformability of the blade edge end. Specifically, it ismost effective to expose the blade base material exclusively at theblade edge end.

(7) Further, in order to prevent partial wear during running-in timewhich is caused by exposure of the blade base material for increasingthe area coming into contact with the cylinder, it is necessary toprovide a coating film having lubricity on surface treated portion ofthe blade edge other than the portion where the base material isexposed.

It has been confirmed that, in order to improve conformability of theblade edge end, in addition to improvement of the ink scraping propertyand property for continuous printing (wear resistance), it is effectiveto form the surface treatment coating film in a double-layered structureto allot different functions to each coating film layer and to exposeonly the blade edge end portion of the blade base material.

That is, the present invention provides the following:

1. A surface treated doctor blade, wherein a surface of at least theblade edge portion of base material comprises a first layer consistingof a nickel-based plating or a chromium-based plating (exclusive of anorganic resin dispersed composite plating in which organic resinparticles are dispersed) and a second layer provided thereon which haslow surface energy.

2. The surface treated doctor blade as described in above item 1,wherein the plating of the first layer is a nickel-phosphorus-basedcomposite plating containing ceramic particles.

3. The surface treated doctor blade as described in above item 2,wherein the particle size of the ceramic particles is 0.05 to 10 μm.

4. The surface treated doctor blade as described in above item 2,wherein the ceramic particles are SiC particles.

5. The surface treated doctor blade as described in above item 1,wherein the second layer is a layer consisting of an organic resindispersed composite plating containing fluorine-based resin particles.

6. The surface treated doctor blade as described in above item 5,wherein the type of the fluorine-based resin particles is at least onetype of particle selected from a group consisting oftetrafluoroethyelene-based resin, perfluoroalkoxy-based resin, andfluorinated ethylene propylene-based resin.

7. The surface treated doctor blade as described in above item 6,wherein the particle size of the fluorine-based resin particles is 0.05to 10 μm.

8. The surface treated doctor blade as described in above item 7,wherein the particle size of the fluorine-based resin particles is notmore than 1.2 times the plating thickness of the second layer.

9. The surface treated doctor blade as described in above item 1,wherein the second layer consists of an organic resin coating film layerhaving low surface energy.

10. The surface treated doctor blade as described in above item 9,wherein the organic resin coating film is at least one type of organicresin coating film selected from silicone-based resin, fluorine-basedresin, and an organic resin containing particles of silicone-based resinand/or fluorine-based resin.

11. The surface treated doctor blade as described in above item 9,wherein the organic resin coating film is at least one type of organicresin coating film selected from a group consisting oftetrafluoroethylene-based resin, perfluoroalkoxy-based resin,fluorinated ethylene propylene-based resin, and an organic resincontaining these resins in the form of particles.

12. The surface treated doctor blade as described in above item 1,wherein blade base material of the blade edge end portion is exposed atleast in a part.

13. The surface treated doctor blade as described in above item 1,wherein Vickers hardness (Hv) of the doctor blade is within a range of400 to 1500.

14. The surface treated doctor blade as described in any one of aboveitems 1 to 13, wherein the sum total of a film thickness (A) of thefirst layer and a film thickness (B) of the second layer is within arange of 2 μm to 30 μm.

15. A surface treated doctor blade as described in above item 14,wherein the ratio (B/A) of the film thickness (B) of the second layer tothe film thickness (A) of the first layer is within a range of 0.005 to1.3.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual drawing illustrating gravure (intaglio) printingusing a doctor blade.

FIG. 2 is a partial enlarged view of FIG. 1.

FIGS. 3(A) and 3 (B) are sectional views showing a blade edge portion ofthe blade of the present invention with its base material being exposedat the edge (tip) end, and FIG. 3(C) is a sectional view showing a bladeedge portion of the blade of the present invention with its basematerial of the edge end portion not being exposed.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail.

In the present invention, any doctor blade base material can be used aslong as it is a publicly-known base material of steel or stainless steelfor use in printing and coating.

Normally, a doctor blade base material undergoes a processing such asstepping so that its side edge constituting the blade edge end portionmay be formed as a sharp edge, and it can assume any one of thefollowing configurations: parallel edge, inclined (bevel) edge, roundedge, and square edge. Further, according to the usage, the presentinvention is applicable to both a one-side type blade in which suchblade edge end processing is conducted only on one side of the blade anda double-side type blade in which such processing is conducted on bothsides of the blade.

In the present invention, there is no limitation regarding the size ofthe blade base material. For example, a typical blade base materialconsists of a band-shaped steel plate having a thickness of 0.15 mm to0.6 mm and a width of 40 to 60 mm.

In the surface treated doctor blade of the present invention, at leastthe surface of the blade edge portion of the base material has adouble-layered structure composed of a first layer consisting of anickel-based plating or a chromium-based plating (exclusive of anorganic resin dispersed composite plating in which organic resinparticles are dispersed) and a second layer having low surface energywhich is provided thereon. More preferably, the second layer consists ofan organic resin dispersed composite plating layer containingfluorine-based resin particles or an organic resin coating layer havinglow surface energy.

The plating of the first layer mainly serves to impart hardness to theblade; a nickel-based plating or a chromium-based plating is effective.It is to be noted that none of nickel-based dispersed composite plating,chromium-based dispersed composite plating in which organic resinparticles are dispersed and plating other than those mentioned above isemployed in the present invention, since such a plating cannot attain apredetermined degree of hardness or does not have sufficientadhesiveness with blade material. Thus, these types of plating are to beexcluded in the present invention.

The term “nickel-based plating” refers to a pure nickel plating, analloy plating such as nickel-cobalt, nickel-iron, nickel-chromium,nickel-tungsten, nickel-manganese, nickel-tin, nickel-phosphorus,nickel-boron, and nickel-phosphorus-boron, or a nickel-based dispersedplating in which particles other than organic resin, for example, atleast one type of particle selected from a group consisting of Al₂O₃,Cr₂O₃, Fe₂O₃, TiO₂, ZrO₂, ThO₂, SiO₂, CeO₂, BeO₂, MgO, CdO, diamond,SiC, TiC, WC, VC, ZrC, TaC, Cr₃C₂, B₄C, BN, ZrB₂, TiN, Si₃N₄, WSi₂, andthe like is dispersed in the matrix composed of those nickel-basedmetals. Any of the above-mentioned platings may be used as thenickel-based plating.

Also, the term “chromium-based plating” refers to a pure chromiumplating, an alloy plating such as chromium-tungsten and chromium-iron,or a chromium-based dispersed plating in which a particle other than anorganic resin, for example, at least one type of particle selected fromAl₂O₃, TiO₂, ZrO₂, SiO₂, CeO₂, UO₂, SiC, WC, ZrB₂, TiB₂, and the like iscontained in the matrix composed of those chromium-based metals. Any ofthe above-mentioned platings may be used as the chromium-based plating.

Note that, in both case of the nickel-based plating and thechromium-based plating, other components such as organic resins, inaddition to the above-mentioned fine particles, can be contained in asmall amount in the matrix as far as the amount is within a range thatdoes not adversely affect the present invention.

Among those nickel-based plating and chromium-based plating, as platingfor a first layer, those in which ceramic particles are dispersed,particularly, nickel-based composite plating in which SiC particles aredispersed is preferred. Among those, the nickel-phosphorous-based alloyplating is most preferred.

Preferably, the particle size of the ceramic particles used in thepresent invention is 0.05 μm to 10 μm. When the particle size is lessthan 0.05 μm or exceeds 10 μm, property for continuous printing (wearresistance), ink scraping property, or adhesion of the platingdeteriorates. In particular, the particle size preferably ranges from0.1 μm to 2 μm, and more preferably, from 0.15 μm to 1 μm.

The ceramic particle content in the plating is preferably 0.5 vol % to40 vol %. When the content is less than 0.5 vol %, the effect ofimproving property for continuous printing (wear resistance) cannot beobtained. When the content exceeds 40 vol %, the plating adhesiondeteriorates undesirably. In particular, the content is preferably 3 vol% to 30 vol %, and more preferably, 5 vol % to 25 vol %.

The coating of the second layer has the following functions:

(1) it lowers surface energy of the blade surface and impartsink-repellency thereto, whereby surplus ink scraped off the non-imageportion is not allowed to stay on the surface, and the discharge of inkto the exterior of the system from the contact area between the cylinderand the blade (portion a in FIG. 2) is facilitated, while intrusion ofink into the contact area between the blade and the cylinder isrestrained; and (2) it improves lubricity at the contact area betweenblade and cylinder, thereby mitigating wear of the blade and thecylinder due to adhesion at the point of contact between the blade andthe cylinder. As the second layer, a low surface energy coating iseffective.

Here, a low surface energy coating means a coating having ink-repellencyand lubricity. Specifically, it is a coating having a surface energylower than at least that of a nickel-phosphorus dispersed plating inwhich SiC is dispersed. In particular, of such low surface energycoatings, an organic resin dispersed nickel-based composite platingcontaining fluorine-based resin particles, and a low surface energyorganic resin coating are preferable. In the following, these twoparticularly preferable coatings will be described in detail.

(a) Organic Resin Dispersed Nickel-Based Composite Plating ContainingFluorine-Based Resin Particles

The particle size of the fluorine-based resin particles used in thiscomposite plating is preferably 0.05 μm to 10 μm. When the particle sizeis less than 0.05 μm, the adhesion with respect to the ground platingdeteriorates, which is undesirable. On the other hand, when the particlesize exceeds 10 μm, the resin particles are likely to come off theplating, making it impossible to obtain the effect of the presentinvention. More preferably, the particle size is 0.07 μm to 5 μm, stillmore preferably, 0.1 μm to 1 μm, and most preferably, 0.15 μm to 0.5 μm.

Further, it is desirable for the resin particle size of thefluorine-based resin be not more than 1.2 times the thickness of theplating layer in which the resin particles are dispersed. When theparticle size exceeds 1.2 times the thickness, the fluorine-based resinis likely to come off the plating, making it impossible to obtain theeffect of the present invention. Moreover, since the protrudingfluorine-based resin excessively protrudes from the plating, printingstreaks due to the fluorine-based resin are likely to be generated,undesirably. More preferably, the particle size is not more than 0.8times the plating thickness, and most preferably, not more than 0.5times the plating thickness.

Examples of the fluorine resin particles include particles of resinssuch as tetrafluoroethylene resin, perfluoroalkoxy resin, fluorinatedethylene propylene resin, tetrafluoroethylene/perfluoroalkyl vinyl ethercopolymer resin, tetrafluoroethylene/ethylene copolymer resin,trifluoroethylene chloride resin and vinylidene fluoride resin. Amongthose resins, tetrafluoroethylene resin, perfluoroalkoxy resin, andfluorinated ethylene propylene resins are preferred. Tetrafluoroethyleneresin is particularly preferred.

Also, as the metal matrix in which fluorine resin particles aredispersed, pure nickel plating, as well as nickel-based alloy platingsuch as nickel-cobalt, nickel-iron, nickel-chromium, nickel-tungsten,nickel-manganese, nickel-tin, nickel-phosphorus, nickel-boron, andnickel-phosphorus-boron are preferred. The nickel-phosphorus alloy isparticularly preferred.

The content of fluorine-based resin particle contained in the plating is2 vol % to 50 vol %. Preferably, it is 10 vol % to 40 vol %, and morepreferably, 20 vol % to 30 vol %.

When the content is less than 2 vol %, it is impossible to obtain theeffect of lowering the surface energy and improving the lubricity. Whenthe content exceeds 50 vol %, the adhesion of the plating deteriorates.

As long as it does not interfere with effects of the present invention,the plating may contain a minute amount of ingredients other than thefluorine-based resin particles.

With a dispersion plating containing particles other than those oforganic resin as dispersion material, it is impossible to obtain asurface having low surface energy and high lubricity required for thepresent invention, and such a dispersion plating is not suitable for thepresent invention. Further, even if contained by the same amount as thefluorine-based resin particles, organic resin particles other thanfluorine-based resin particles cannot lower surface energy or improvelubricity to the same degree as fluorine-based resin particles can. Inorder for such resin particles to contribute to obtaining the same levelof low surface energy as that obtained by using fluorine-based resinparticles, the resin content in the plating has to be considerablyexcessive, making it impossible to obtain good adhesion of plating andwear resistance as required in the present invention.

(b) Organic Resin Films Having Low Surface Energy

Examples of the organic resin films having low surface energy include:perfluorolauric acid film; paraffin-based resin; polyolefin-based resinssuch as polyethylene and polypropylene; fluorine-based resins such astetrafluoroethylene resin, perfluoroalkoxy resin, fluorinated ethylenepropylene resin, tetrafluoroethylene/perfluoroalkyl vinyl ethercopolymer resin, tetrafluoroethylene/ethylene copolymer resin,trifluoroethylene chloride resin, vinylidene fluoride resin,perfluorooctylethyl acrylate resin, fluorinated acrylic polymer, andfluorinated methacrylic polymer; silicone-based resin; imine-basedresin; urethane-based resin, acrylic-based resin; and films comprisingat least one resin selected from organic resins which contain theabove-mentioned resin as particles. Among those, fluorine-based resin,silicone-based resin, and organic resin which contain particles of thosefluorine-based resins or those silicone-based resins are preferred.Tetrafluoroethylene-based resins, perfluoroalkoxy-based resin,fluorinated ethylene propylene-based resins, perfluorooctylethylacrylate resins, and organic resins which contain particles composed ofthose resins are particularly preferred.

An organic film other than the above cannot provide a low surface energyor is not resistant to ink, making it impossible to obtain the effect ofthe present invention.

Also, when resin particles of silicone-based resin or fluorine-basedresin are dispersed in the organic resin, it is desirable that theparticle size of the resin particles be 0.05 μm to 10 μm. When theparticle size is less than 0.05 μm, the adhesion with respect to theground plating deteriorates undesirably. On the other hand, the resinparticles of a particle size exceeding 10 μm, which are likely to comeoff the coating, are not suitable for the present invention to obtainthe effect of the present invention. The particle size is preferably 0.1μm to 3 μm, and more preferably, 0.15 μm to 0.8 μm. The content of suchresin particles is preferably 2 vol % to 50 vol %, and more preferably,5 vol % to 35 vol %.

The organic resin used as the binder of the resin particles is selectedfrom the viewpoint of resistance to ink. Examples of the organic resinto be used include acrylic resin, urethane-based resin, phenol-basedresin, epoxy-based resin, imine-based resin, and polyolefin-based resin.

In the present invention, as long as it does not impair its effects,organic coating of the second layer can contain antirust pigment,extender pigment, coloring pigment, dye, etc.

The composite effects of the present invention can be obtained onlythrough a combination of the first layer consisting of a specificnickel-based plating and the second layer consisting of a low surfaceenergy film. When used alone, neither of these layers provides theeffects of the present invention.

In the present invention, it is desirable that the degree of the surfacehardness of the surface treated blade edge portion be 400 to 1500 inVickers hardness (Hv). When its Vickers hardness (Hv) is less than 400,a failure in scraping ink off is likely to occur, and a printing defectsuch as defective image configuration is likely to be generated in theearly stage of continuous printing. Further, property for continuousprinting (wear resistance) also deteriorates. On the other hand, whenthe Vickers hardness exceeds 1500, the plating becomes brittle to beeasily peeled off. Moreover, the blade will damage the plate surface ofthe cylinder, resulting in a printing failure. In particular, theVickers hardness (Hv) is preferably 700 to 1300 and, more preferably,800 to 1150.

In the present invention, the Vickers hardness (Hv) is measuredaccording to the Vickers hardness test as prescribed in themicrohardness test method of JIS Z 2251 (Regarding the test load, a loadof less than 50 gf may be appropriately selected for use according tothe coating film thickness).

In the present invention, the film thickness of the surface treatmentcoating film is determined such that the sum total film thickness (A+B)of film thickness (A) of the first layer and film thickness (B) of thesecond layer, is 2 μm to 30 μm. When the sum total coating filmthickness of the two layers is less than 2 μm, it is impossible toobtain the effect of property for continuous printing (wear resistance),and therefore such a thickness is not suitable for the presentinvention. On the other hand, sum total coating film thickness exceeding30 μm is disadvantageous from the economical viewpoint, and is notsuitable for the present invention since property for continuousprinting (wear resistance) and adhesion of the coating deteriorate. Inparticular, the total film thickness A+B is preferably within a range of3 μm to 15 μm, and more preferably, within a range of 5 μm to 10 μm.

Further, it is desirable that the ratio (B/A) of the thickness (B) ofthe second layer to the thickness (A) of the first layer be not lessthan 0.005 and not more than 1.3. When the coating film thickness ratiois less than 0.005, ink scraping failure is likely to occur. When theratio exceeds 1.3, property for continuous printing (wear resistance)deteriorates. In particular, the coating film thickness ratio B/A ispreferably not less than 0.05 and not more than 0.6, and morepreferably, not less than 0.1 and not more than 0.3.

A known measurement method can be employed for measurement of theplating thickness and the resin coating film thickness.

Examples of known measurement methods include: (1) a method in whichfilm thickness is measured by using a fluorescent X-ray measurementapparatus, (2) a method in which the surface treatment coating is peeledoff by means of a stripping solution to measure the film thickness basedon the difference in weight before and after peeling, and (3) a methodin which the vertical section is observed by an optical microscope or anelectronic microscope to measure the plating thickness and the resincoating film thickness.

As a specific means for surface treatment, it is possible to adopt anyone of known production techniques. For example, when the second layeris a plating coating, production may proceed through the followingsequence of steps: degreasing, rinsing, activation, rinsing, plating,rinsing, plating, rinsing, and then drying, or the sequence of steps:degreasing, rinsing, activation, rinsing, plating, rinsing, (surfaceadjustment by at least one of the following: degreasing, acid treatment,polishing, rinsing, etc.), plating, rinsing, and then drying. When thesecond layer is a resin coating, production may proceed through thefollowing sequence of steps: degreasing, rinsing, activation, rinsing,plating, rinsing, drying, coating, and baking, or the sequence of steps:degreasing, rinsing, activation, rinsing, plating, rinsing, drying,annealing, (in some cases, pre-treatment (degreasing, rinsing, etc.),drying), coating, and then drying/baking. On the blade which hasundergone the above surface treatment, an appropriate combination ofpost-treatments such as annealing, surface polishing, blade edgeadjustment, anti-corrosive oil application, and shearing into apredetermined size are conducted, whereby it is possible to obtain adesired doctor blade.

As plating means, publicly-known plating technique, such aselectroplating or electroless plating may be employed.

As coating means, publicly-known coating process, such as bar coatermethod, roll coater method, brush application, spray method, orimmersion method may be employed, to apply a coating material consistingof a predetermined resin to a predetermined thickness.

As means for drying the coating layer, publicly-known drying means, suchas a hot-air drying furnace or an induction heater may be employed.

In the present invention, in order to improve the adhesion between theblade base material and the plating of the first layer and/or betweenthe plating of the first layer and the second layer coating film and topromote the deposition of the plating coating, a ground plating may beperformed in advance using nickel-based plating, copper type plating orthe like as the ground treatment of the plating of the first layerand/or the second layer coating film. In particular, when a stainlesssteel material is used as the blade base material, it is effective toperform nickel-based strike plating as the ground plating prior to theplating of the first layer.

As described above, the surface treated doctor blade of the presentinvention is coated with the above-described specific surface treatmentcoating of a double-layered structure, whereby it is possible to obtainthe effect of the present invention (property for continuous printing(wear resistance) and ink scraping property).

Further, by exposing the doctor blade base material at the blade edgeend portion, conformability between the cylinder and the blade edge endis improved, thereby shortening running-in time.

Regarding the exposure of the base material at the blade edge portion,it is only necessary for at least a part of the blade base material atthe blade edge end portion to be exposed. For example, the exposure canbe effected as shown in the sectional views of FIGS. 3(A) and 3 (B),illustrating the blade edge end portion (5). In the case in which bladeedge end conformability is more important than property for continuousprinting, the mode as shown in FIG. 3(A) may be suitably adopted, inwhich the blade edge end is formed so as to exhibit a specific angle(e.g., blade edge end angle α: 10° to 70°), with the blade base material(7) being exposed. In the case in which property for continuous printingis more important than conformability of the blade edge end, the mode asshown in FIG. 3(B) may be suitably adopted, in which the blade basematerial is exposed exclusively at the forwardmost end of the bladeedge. In this way, regarding the exposure of the blade base material ofthe blade edge end, the way the blade base material is exposed can besuitably adjusted according to the printing system and the performancerequired.

Further, the blade edge portion other than the portion (6) where bladebase material is exposed is characteristically coated with a surfacetreatment coating (8) having a specific double-layered structure. Thatis, it has to be coated with a surface treatment coating composed of afirst layer consisting of a specific nickel-based plating orchromium-based plating and a second layer provided thereon andconsisting of a low surface energy coating. With any other surfacetreatment coating, it is impossible to obtain a surface treated doctorblade which is superior in blade edge end conformability, ink scrapingproperty, and property for continuous printing (wear resistance).

A blade whose base material is exposed at least partially at the bladeedge end portion can be produced, for example, by the following sequenceof steps: “sealing of the blade edge end portion of the blade basematerial with a masking agent”, “surface treatment”, “peeling of themasking agent”, “annealing”, “shearing in a predetermined size”,“surface treatment”, “polishing of exclusively the blade edge endportion with buff, abrasive paper or the like”, “annealing”, and“shearing in a predetermined size”, or by the following sequence ofsteps: “surface treatment”, “polishing of exclusively the blade edge endportion with buff, abrasive paper or the like”, “annealing”, “polishingof exclusively the blade edge end portion with buff, abrasive paper orthe like”, and “shearing in a predetermined size”. Further, as apost-treatment, it is possible to perform surface polishing,anti-corrosive oil application, etc.

The embodiments of the present invention do not limit treatmentsperformed on portions other than the blade edge end portion inaccordance with the present invention. For example, the followingembodiments of the surface treated doctor blade can be adopted withoutinvolving any problem:

(1) an embodiment in which double-layered coating according to thepresent invention is performed on the entire surface of a blade on bothsides thereof (i.e., on the front side (S-side in FIG. 2) and the backside (R-side in FIG. 2) with respect to the cylinder rotatingdirection);

(2) an embodiment in which double-layered coating according to thepresent invention is performed on the entire surface of a blade on oneside thereof; specifically, double-layered coating according to thepresent invention is performed on the front side of the blade edge end(S-side in FIG. 2), and the back side of the blade edge end (R-side inFIG. 2) is subjected to nickel-based plating or chromium-based platingor left without being plated with its steel surface exposed;

(3) an embodiment in which double-layered coating according to thepresent invention is performed at least on the blade edge on both sidesthereof (S-side and R-side in FIG. 2); and

(4) an embodiment in which double-layered coating according to thepresent invention is performed at least on one side of the blade edge;specifically, the front side (S-side in FIG. 2) of the blade edge end issubjected to double-layered coating according to the present invention,and the back side (R-side in FIG. 2) of the blade edge end is subjectedto nickel-based plating or chromium-based plating or left without beingplated with its steel surface exposed.

Further, in all of the above modes (1) to (4), the base material of adoctor blade at least at the blade edge end portion thereof may beexposed in order to improve conformability of the blade edge end.

The surface treated doctor blade of the present invention is applicableto printing such as gravure printing. Further, it can also beappropriately applied to other uses, such as painting, coating orremoval of residual toner in an image forming apparatus. The ink orpaint used in printing or painting may be a water-based or oil-basedone. Further, in the present invention, there is no limitation regardingthe inking system of the printing machine as long as it is a systemusing a blade; it may be, for example, a dip brazing system or afurnisher roller system.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention will now be described with reference to examplesand comparative examples, which should not be construed restrictively.

In the examples and comparative examples, the degree of surfacehardness, coating film thickness, and surface energy of the surfacetreated doctor blade were measured by the following methods.

Surface Hardness (Vickers Hardness)

5-point measurement was performed under the following conditions, andthe average value thereby obtained was regarded as the Vickers hardness(Hv).

Measurement position: the front side (with respect to the roll rotatingdirection, i.e., S-side in FIG. 2) of the blade edge end portion;

Measuring apparatus: HMV-2000 manufactured by Shimadzu Corporation;

Measurement condition: a test load of 25 gf and a retention time of 10seconds.

Film Thickness

The section of the blade edge was observed by an electronic microscopeto measure the film thickness of each layer.

Surface Energy

A drop of water was put on the surface of the surface treated portion ofthe blade edge, and the contact angle made by the drop of water and thesurface (the water contact angle) was measured, and compared with thewater contact angle in a blade with an SiC dispersed nickel-phosphoruscomposite single-layer plating described below (Comparative Example 1),utilizing the comparison result as a yardstick for surface energy.

High surface energy: The contact angle is the same as or smaller thanthat in the blade with the SiC dispersed nickel-phosphorus compositesingle-layer plating (Comparative Example 1).

Low surface energy: The contact angle is the same as or larger than thatin the blade with the SiC dispersed nickel-phosphorus compositesingle-layer plating (Comparative Example 1).

EXAMPLE 1

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (steelstrip having a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm was spirally taken up on a reel togetherwith a spacer consisting of a metal steel strip which had the surfaceroughened by embossing treatment, and in the state in which it was woundaround the reel, it was immersed for 15 minutes in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.), 60g/L) of 50° C. After being washed in water, it was subjected to ahydrochloric acid activation treatment in a hydrochloric acid activationliquid for 15 minutes, and was then further washed in water. Thereafter,it was immersed in an electroless Ni plating solution in which SiCparticles having an average particle size of 0.5 μm were dispersed(plating solution manufactured by Japan Kanigen Co., Ltd.; SumerSC-80-1: 20 vol %, Sumer SC-80-4; 2 vol %) at 87° C. until apredetermined plating thickness was attained to effect ceramic dispersednickel-phosphorus composite plating containing SiC. After being washedin water, the specimen was dried. Thereafter, the spacer and the bladewere unwound and separated to obtain a blade 1 having anSiC-particle-containing nickel-phosphorus-based composite (Ni—P—SiC)single layer plating.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a smooth, single-layer-plated blade 2.

Plating Process 2;

The single-layer-plated blade 2 was again spirally taken up on the reeltogether with the spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed for 5 minutes in an alkalidegreasing solution (Pakuna RT-T (manufactured by Yuken Industry Co.,Ltd.) 50 g/L) of 50° C. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 3 minutes, and was further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which tetrafluoroethylene resin (1) was dispersed (a platingsolution manufactured by Japan Kanigen Co., Ltd. (Kaniflon-0: 20 vol %,Kaniflon-4A (a solution in which tetrafluoroethylene resin (1) isdispersed): 2 vol %, pH 5) at 86° C. until a predetermined platingthickness was attained to effect an organic resin dispersednickel-phosphorus composite plating containing tetrafluoroethyleneresin, and then the specimen was washed in water and dried. Thereafter,the spacer and the blade were unwound and separated to obtain adouble-layer-plated blade 1 having a first layer consisting of Ni—P—SiCplating and a second layer provided thereon and consisting of anickel-phosphorus-based composite plating layer (Ni—P-PTFE (1))containing particles of tetrafluoroethylene resin (1).

Post-Treatment Process;

Annealing was performed on the above-described blade 1 havingdouble-layered plating at 300° C. for an hour, and then the blade wassheared in a predetermined size. The Vickers hardness (Hv), platingthickness, and surface energy of this surface treated doctor blade weremeasured. Table 1 collectively shows the values of the thickness (A) ofthe first layer, the thickness (B) of the second layer, the totalthickness (A+B), the thickness ratio (B/A), the tetrafluoroethyleneresin content in the second layer, the ratio of the particle size of thetetrafluoroethylene resin with respect to the thickness (B) of thesecond layer, the surface energy of the second layer, and the Vickershardness (Hv).

(1) Continuous Printing Property (Wear Resistance)

After adjustment of conformability of the blade edge end, printing wasperformed by a printing machine in which the blade of Example 1 wasmounted, using an oil-based ink and a water-based ink. The point in timewhen a printing failure such as a streak, fog, blurring, or bleeding wasgenerated in the print was determined as the end of its service life ofthe blade. The amount of prints obtained until the blade reached the endof the service life was measured, and compared with the amount of printsobtained in the case of a blade with an SiC dispersed nickel-phosphoruscomposite single-layer plating (Comparative Example 1). Evaluation wasmade according to the following criteria. With water-based ink Withoil-based ink ⊚ 1 1 ◯ 2 1 Δ 3 2 to 3 X 4 4Evaluation Criteria

1: The amount of prints is much larger than that in the case where theblade having the SiC dispersed nickel-phosphorus composite single-layerplating was used(Comparative Example 1).

2: The amount of prints is a little larger than that in the case wherethe blade having the SiC dispersed nickel-phosphorus compositesingle-layer plating was used (Comparative Example 1).

3: The amount of prints is equal to that in the case where the bladehaving the SiC dispersed nickel-phosphorus composite single-layerplating was used (Comparative Example 1).

4: The amount of prints is smaller than that in the case where the bladehaving the SiC dispersed nickel-phosphorus composite single-layerplating was used (Comparative Example 1).

(2) Ink Scraping Property

Using a water-based ink, printing was performed with a gravure printingmachine in which the blade of Example 1 was mounted. The printing speedin printing was gradually changed, and the printing speed at which anink scraping failure (fog or the like) started to be generated wasmeasured. The measured printing speed was regarded as the printing speedlimit, which was evaluated by the following criteria, in comparison withthat in the case where a steel product with no plating was used:

-   -   ⊚: The printing speed limit is not less than 1.4 times that in        the case of the steel product.    -   ◯: The printing speed limit is not less than 1.1 times and less        than 1.4 times that in the case of the steel product.    -   Δ: The printing speed limit is not less than 1.0 times and less        than 1.1 times that in the case of the steel product.    -   X: The printing speed limit is less than 1.0 times that in the        case of the steel product.        (3) Coating Adhesion

A surface treated doctor blade was bent at a predetermined angleaccording to JIS H 8504, a tape peel test was then conducted on the bentportion, and it was visually observed whether or not the coating film ispeeled off. Evaluation was made according to the following criteria:

-   -   ⊚: Satisfactory (no coating film was peeled off)    -   Δ: A little defective (a small amount of the coating film was        peeled off)    -   X: Defective (a large amount of the coating film was peeled off)

Table 1 collectively shows the evaluation results regarding property forcontinuous printing (wear resistance), ink scraping property, andcoating film adhesion.

EXAMPLE 2

Plating Process;

A single-and-parallel-edged steel base material for doctor blade (steelstrip having a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm was spirally taken up on a reel togetherwith a spacer consisting of a rough wire mesh, and in the state in whichit was wound around the reel, it was immersed for 15 minutes in analkali degreasing solution (Pakuna RT-T (manufactured by Yuken IndustryCo., Ltd.), 60 g/l) of 50° C. After being washed in water, it wassubjected to a hydrochloric acid activation treatment in a hydrochloricacid activation liquid for 15 minutes, and was then further washed inwater. Thereafter, it was immersed in an electroless Ni plating solutionin which SiC of an average particle size of 0.5 μm were dispersed(plating solution manufactured by Japan Kanigen Co., Ltd.; SumerSC-80-1: 20 vol %, Sumer SC-80-4; 2 vol %) at 87° C. until apredetermined plating thickness was attained to effect ceramic dispersednickel-phosphorus composite plating containing SiC (Ni—P—SiC). Afterbeing washed in water, it was further immersed in an electroless Niplating solution in which tetrafluoroethylene resin (1) was dispersed (aplating solution manufactured by Japan Kanigen Co., Ltd. ((Kaniflon-0:20 vol %, Kaniflon-4A (a liquid in which tetrafluoroethylene resin (1)is dispersed): 2 vol %, pH 5) at 86° C. until a predetermined platingthickness was attained to effect an organic resin dispersednickel-phosphorus composite plating containing tetrafluoroethyleneresin. After being washed in water, the specimen was dried. Thereafter,the spacer and the blade were unwound and separated to obtain adouble-layer-plated blade 1 having a first layer consisting of Ni—P—SiCplating and a second layer provided thereon and consisting of anickel-phosphorus-based composite plating layer (Ni—P-PTFE (1))containing particles of tetrafluoroethylene resin (1).

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned double-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a smooth, double-layer-plated blade 2.

Post-Treatment Process;

The above double-layer-plated blade 2 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size. Table 1 showsthe measurement and evaluation results regarding the Vickers hardness(Hv), plating thickness, surface energy of the second layer, propertyfor continuous printing, ink scraping property, plating adhesion, etc.obtained in the same manner as in Example 1.

COMPARATIVE EXAMPLE 1

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60 g/L)of 50° C. for 15 minutes. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 15 minutes and further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which SiC of an average particle size of 0.5 μm wasdispersed (a plating solution manufactured by Japan Kanigen Co., Ltd.;SC-80-1: 20 vol %, SC-80-4: 2 vol %; pH 4.7) at 87° C. until apredetermined plating thickness was attained to effect ceramic dispersednickel-phosphorus composite plating containing SiC. After being washedin water, the specimen was dried. Thereafter, the spacer and the bladewere unwound and separated to thereby obtain a blade 1 plated with anSiC particle-containing nickel-phosphorus-based composite (Ni—P—SiC)single layer plating.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a smooth, single-layer-plated blade 2.

Post-Treatment Process;

The above single-layer-plated blade 2 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size. Table 1 showsthe measurement and evaluation results regarding the Vickers hardness(Hv), plating thickness, property for continuous printing, ink scrapingproperty, plating adhesion, etc. obtained in the same manner as inExample 1.

COMPARATIVE EXAMPLE 2

Plating Process;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60 g/L)of 50° C. for 15 minutes. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 15 minutes and further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which tetrafluoroethylene resin wass dispersed (a platingsolution manufactured by Japan Kanigen Co., Ltd. ((Kaniflon-0: 20 vol %,Kaniflon-4A (a solution in which tetrafluoroethylene resin (1) isdispersed): 2 vol %, pH 5) at 86° C. until a predetermined platingthickness was attained to effect an organic resin dispersednickel-phosphorus composite plating containing tetrafluoroethyleneresin. After being washed in water, the specimen was dried. Thereafter,the spacer and the blade were unwound and separated to thereby obtain ablade 1 plated with a single layer of a tetrafluoroethylene resin(1)-particle-containing nickel-phosphorus-based composite plating(Ni—P-PTFE (1)).

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Post-Treatment Process;

The above single-layer-plated blade 2 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size. Table 1 showsthe measurement and evaluation results regarding the Vickers hardness(Hv), plating thickness, property for continuous printing, ink scrapingproperty, plating adhesion, etc. obtained in the same manner as inExample 1.

COMPARATIVE EXAMPLES 3 and 4 and EXAMPLES 3 to 33

As in Example 1, a single-and-parallel-edged steel base material fordoctor blade (steel strip having a total length of 50 m) having a platewidth of 50 mm, a plate thickness of 0.15 mm, a blade edge width of 1.4mm, and a blade edge end thickness of 0.07 mm was appropriatelysubjected to a pre-treatment, and then various plating processes wereperformed thereon to prepare the surface treated doctor blades ofComparative Examples 3 and 4 and Examples 3 to 33 as shown in Table 1.Table 1 shows the measurement and evaluation results obtained in thesame manner as in Example 1 regarding the Vickers hardness (Hv), platingthickness, surface energy, property for continuous printing, inkscraping property, and plating adhesion of these surface treated doctorblades. Table 2 shows the average particle sizes of eight types oftetrafluoroethylene resin particles (PTFE (1) to PTFE (8)) dispersed inthe plating. The average particle size of the SiC particles used was 0.5μm.

EXAMPLE 34

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was continuously subjected toelectrolysis (Pakuna Erekuta J (manufactured by Yuken Industry Co.,Ltd.): 50 m/l, NaOH: 50 g/l, 30° C., 2.5 A) and washed in water.Thereafter, electric chromium plating (chromic anhydride: 250 g/l,H₂SO₄: 2.5 g/L, HEEF25C: 20 ml/l, bath temperature: 50° C.) wasperformed on the specimen, adjusting the plating current and platingtime so as to attain a predetermined plating thickness, to therebyprepare a single-layer chromium-plated blade 1.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layerchromium-plated blade 1 to completely remove the plating residues or thelike from the surface, thereby obtaining a single-layer chromium-platedblade 2.

Plating Process 2;

The single-layer chromium-plated blade 2 was again spirally taken up onthe reel together with the spacer consisting of a metal steel stripwhich had the surface roughened by embossing treatment, and in the statein which it was wound around the reel, it was immersed for 5 minutes inan alkali degreasing solution (Pakuna RT-T (manufactured by YukenIndustry Co., Ltd.) 50 g/L) of 50° C. After being washed in water, thespecimen was subjected to hydrochloric acid activation treatment in ahydrochloric acid activation solution for 3 minutes, and was furtherwashed in water. Thereafter, the specimen was immersed in an electrolessNi plating solution in which tetrafluoroethylene resin (1) was dispersed(a plating solution manufactured by Japan Kanigen Co., Ltd. (Kaniflon-0:20 vol %, Kaniflon-4A (a solution in which tetrafluoroethylene resin (1)is dispersed): 2 vol %, pH: 5) at 86° C. until a predetermined platingthickness was attained to effect an organic resin dispersednickel-phosphorus composite plating containing tetrafluoroethyleneresin, and then the specimen was washed in water and dried. Thereafter,the spacer and the blade were unwound and separated to obtain adouble-layer-plated blade 1 having a first layer consisting of chromium(Cr) plating and a second layer provided thereon and consisting of anickel-phosphorus-based composite plating layer (Ni—P-PTFE (1))containing particles of tetrafluoroethylene resin (1).

Post-Treatment Process;

The above double-layer-plated blade 1 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size. Table 1 showsthe measurement and evaluation results regarding the Vickers hardness(Hv), plating thickness, surface energy of the second layer, propertyfor continuous printing, ink scraping property, plating adhesion, etc.obtained in the same manner as in Example 1. TABLE 1 Surface treateddoctor blade and properties First layer Second layer PTFE Film PTFE Filmgrain size/ thickness content thickness Surface film thickness No. Type(A)(μm) Type (vol %) (B) (μm) energy (B) Example 1 Ni—P—SiC 6Ni—P-PTFE(1) 20 to 25 1 Low 0.22 2 Ni—P—SiC 7 Ni—P-PTFE(1) 20 to 25 1Low 0.22 3 Ni—P—SiC 6 Ni—P-PTFE(1) 3 to 7 1 Low 0.22 4 Ni—P—SiC 6Ni—P-PTFE(1) 10 to 15 1 Low 0.22 5 Ni—P—SiC 6 Ni—P-PTFE(1) 30 to 35 1Low 0.22 6 Ni—P—SiC 6 Ni—P-PTFE(1) 45 to 50 1 Low 0.22 7 Ni—P—SiC 6Ni—P-PTFE(2) 20 to 25 1 Low 0.06 8 Ni—P—SiC 6 Ni—P-PTFE(3) 20 to 25 1Low 0.12 9 Ni—P—SiC 6 Ni—P-PTFE(4) 20 to 25 1 Low 0.15 10 Ni—P—SiC 6Ni—P-PTFE(5) 20 to 25 1 Low 0.35 11 Ni—P—SiC 7 Ni—P-PTFE(6) 20 to 25 2Low 0.35 12 Ni—P—SiC 7 Ni—P-PTFE(7) 20 to 25 2 Low 0.75 13 Ni—P—SiC 7Ni—P-PTFE(8) 20 to 25 2 Low 3.0 14 Ni—P—SiC 4.5 Ni—P-PTFE(5) 20 to 250.5 Low 0.7 15 Ni—P—SiC 6 Ni—P-PTFE(1) 20 to 25 1 Low 0.22 16 Ni—P—SiC 6Ni—P-PTFE(1) 20 to 25 1 Low 0.22 17 Ni—P—SiC 6 Ni—P-PTFE(1) 20 to 25 1Low 0.22 18 Ni—P—SiC 6 Ni—P-PTFE(1) 20 to 25 1 Low 0.22 19 Ni—P—SiC 6Ni—P-PTFE(1) 20 to 25 1 Low 0.22 20 Ni—P—SiC 6 Ni—P-PTFE(1) 20 to 25 1Low 0.22 21 Ni—P—SiC 6 Ni—P-PTFE(1) 20 to 25 1 Low 0.22 22 Ni—P—SiC 2.1Ni—P-PTFE(1) 20 to 25 0.4 Low 0.38 23 Ni—P—SiC 3.3 Ni—P-PTFE(1) 20 to 250.7 Low 0.31 24 Ni—P—SiC 5 Ni—P-PTFE(1) 20 to 25 1 Low 0.22 25 Ni—P—SiC10 Ni—P-PTFE(1) 20 to 25 2 Low 0.11 26 Ni—P—SiC 16 Ni—P-PTFE(1) 20 to 254 Low 0.06 27 Ni—P—SiC 21 Ni—P-PTFE(1) 20 to 25 4 Low 0.06 28 Ni—P—SiC7.7 Ni—P-PTFE(4) 20 to 25 0.3 Low 0.50 29 Ni—P—SiC 7.5 Ni—P-PTFE(1) 20to 25 0.5 Low 0.42 30 Ni—P—SiC 7.1 Ni—P-PTFE(1) 20 to 25 0.9 Low 0.26 31Ni—P—SiC 6.2 Ni—P-PTFE(1) 20 to 25 1.8 Low 0.12 32 Ni—P—SiC 5.3Ni—P-PTFE(1) 20 to 25 2.7 Low 0.08 33 Ni—P—SiC 3.6 Ni—P-PTFE(1) 20 to 254.4 Low 0.05 34 Cr 6 Ni—P-PTFE(1) 20 to 25 1 Low 0.22 Comparative 1Ni—P—SiC 8 — — — — Example 2 Ni—P- 7 — — — — PTFE(1)*1 3 Ni—P- 6Ni—P—SiC 1 High — PTFE(1)*1 4 Ni—P—SiC 6 Ni—P 0 1 High — Total film FilmContinuous Ink thickness thickness Hardness printing scraping CoatingNo. (A + B) ratio (B/A) (Hv) characteristic property adhesion Example 17 0.17 1000 ⊚ ⊚ ◯ 2 8 0.14 1000 ⊚ ⊚ ◯ 3 7 0.17 1000 ◯ ◯ ◯ 4 7 0.17 1000⊚ ◯ ◯ 5 7 0.17 1000 ◯ ⊚ ◯ 6 7 0.17 1000 ◯ ◯ Δ 7 7 0.17 1000 Δ ⊚ Δ 8 70.17 1000 ◯ ⊚ ◯ 9 7 0.17 1000 ⊚ ⊚ ◯ 10 7 0.17 1000 ⊚ ⊚ ◯ 11 9 0.29 1000⊚ ◯ ◯ 12 9 0.29 1000 ◯ ◯ ◯ 13 9 0.29 1000 Δ ⊚ Δ 14 5 0.11 1000 ◯ ⊚ Δ 157 0.17 500 Δ ◯ ◯ 16 7 0.17 750 ◯ ⊚ ◯ 17 7 0.17 850 ⊚ ⊚ ◯ 18 7 0.17 900 ⊚⊚ ◯ 19 7 0.17 1100 ⊚ ⊚ ◯ 20 7 0.17 1200 ◯ ⊚ ◯ 21 7 0.17 1350 Δ ◯ Δ 222.5 0.19 720 Δ ⊚ ⊚ 23 4 0.21 900 ◯ ⊚ ◯ 24 6 0.20 1000 ⊚ ⊚ ◯ 25 12 0.201000 ◯ ⊚ ◯ 26 20 0.25 1000 ◯ ⊚ Δ 27 25 0.19 1000 Δ ◯ Δ 28 8 0.04 1100 ◯Δ ◯ 29 8 0.07 1100 ⊚ ◯ ◯ 30 8 0.12 1000 ⊚ ⊚ ◯ 31 8 0.29 1000 ⊚ ⊚ ◯ 32 80.50 900 ◯ ⊚ ◯ 33 8 1.22 750 Δ ◯ ◯ 34 7 0.17 900 ◯ ⊚ ◯ Comparative 1 8 —1000 Δ X ◯ Example 2 7 — 500 X X ◯ 3 7 0.17 900 X X X 4 7 0.17 900 Δ X ◯*1PTFE content is 20 to 25 vol %

TABLE 2 Particle size of PTFE Particle size (μm) PTFE(1) 0.22 PTFE(2)0.06 PTFE(3) 0.12 PTFE(4) 0.15 PTFE(5) 0.35 PTFE(6) 0.7 PTFE(7) 1.5PTFE(8) 6

EXAMPLE 35

Plating Process;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, the specimen was immersed for 15 minutes inan alkali degreasing solution (Pakuna RT-T (manufactured by YukenIndustry Co., Ltd.); 60 g/liter) of 50° C. After being washed in water,the specimen was subjected to hydrochloric acid activation treatment ina hydrochloric acid activation solution for 15 minutes, and was furtherwashed in water. Thereafter, the specimen was immersed in an electrolessNi plating solution in which SiC particles with an average particle sizeof 0.5 μm were dispersed (a plating solution manufactured by JapanKanigen Co., Ltd., Sumer SC-80-1: 20 vol %, Sumer SC-80-4: 2 vol %) at87° C. until a predetermined plating thickness was attained to therebyeffect a ceramic dispersed nickel-phosphorus composite platingcontaining SiC particles. After being washed in water, the specimen wasdried. Thereafter, the spacer and the blade were unwound and separatedto thereby obtain a blade 1 with an SiC particle dispersednickel-phosphorus-based composite (Ni—P—SiC) single layer plating.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface. After performing annealing at 300° C. for an hour, there wasobtained a single-layer-plated blade 2.

Coating Process;

An acrylic resin coating material containing tetrafluoroethylene resin(5) (PTFE (5)) was applied to the single-layer-plated blade 2 by using aroll coater such that the film thickness when dried was 1 μm, and thendried in a hot-air drying furnace. Thereafter, the specimen was shearedin a predetermined size to thereby obtain a double-layered surfacetreated doctor blade according to the present invention. The Vickershardness (Hv), film thickness of each layer, and surface energy of thissurface treated doctor blade were measured. Further, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were evaluated in the same manner asin Example 1.

Table 3 shows the results of measurement and evaluation of the thickness(A) of the first layer, second layer thickness (B), total layerthickness (A+B), layer thickness ratio (B/A), the mount oftetrafluoroethylene resin contained in the second layer, Vickershardness (Hv), surface energy of the second layer, property forcontinuous printing, ink scraping property, coating film adhesion, etc.Table 4 shows the particle size of the PTFE (5) particles dispersed inthe coating layer.

COMPARATIVE EXAMPLE 5

Plating Process;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, the specimen was immersed for 15 minutes inan alkali degreasing solution (Pakuna RT-T (manufactured by YukenIndustry Co., Ltd.); 60 g/l) of 50° C. After being washed in water, thespecimen was subjected to hydrochloric acid activation treatment in ahydrochloric acid activation solution for 15 minutes, and was furtherwashed in water. Thereafter, the specimen was immersed in an electrolessNi plating solution in which SiC particles with an average particle sizeof 0.5 μm are dispersed (a plating solution manufactured by JapanKanigen Co., Ltd., Sumer SC-80-1: 20 vol %, Sumer SC-80-4: 2 vol %, pH4.7) at 87° C. until a predetermined plating thickness was attained tothereby effect a ceramic dispersed nickel-phosphorus composite platingcontaining SiC particles. After being washed in water, the specimen wasdried. Thereafter, the spacer and the blade were unwound and separatedto thereby obtain a blade 1 plated with an SiC particle-containingnickel-phosphorus-based composite (Ni—P—SiC) single layer plating.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Post-Treatment Process;

The above single-layer-plated blade 2 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size.

Table 3 shows the measurement and evaluation results regarding theVickers hardness (Hv), plating thickness, property for continuousprinting, ink scraping property, and coating film adhesion obtained inthe same manner as in Example 35.

COMPARATIVE EXAMPLE 6

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, the specimen was immersed for 15 minutes inan alkali degreasing solution (Pakuna RT-T (manufactured by YukenIndustry Co., Ltd.); 60 g/l) of 50° C. After being washed in water, thespecimen was subjected to hydrochloric acid activation treatment in ahydrochloric acid activation solution for 15 minutes, and was furtherwashed in water. Thereafter, the specimen was immersed in an electrolessNi plating solution in which tetrafluoroethylene resin (1) is dispersed(a plating solution manufactured by Japan Kanigen Co., Ltd., Kaniflon-0:20 vol %, Kaniflon-4A (a liquid in which tetrafluoroethylene resin (1)is dispersed): 2 vol %, pH 5) at 86° C. until a predetermined platingthickness was attained to thereby effect an organic resin dispersednickel-phosphorus composite plating containing tetrafluoroethyleneresin. After being washed in water, the specimen was dried. Thereafter,the spacer and the blade were unwound and separated to thereby obtain ablade 1 plated with a single layer of a tetrafluoroethylene resin(1)-particle-containing nickel-phosphorus-based composite plating(Ni—P-PTFE (1)).

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Post-Treatment Process;

The above single-layer-plated blade 2 was subjected to annealing at 300°C. for an hour, and then sheared in a predetermined size.

Table 3 shows the measurement and evaluation results regarding theVickers hardness (Hv), plating thickness, property for continuousprinting, ink scraping property, and coating film adhesion obtained inthe same manner as in Example 35.

EXAMPLES 36 to 64 and COMPARATIVE EXAMPLES 7 and 8

As in Example 35, a single-and-parallel-edged steel base material fordoctor blade (steel strips having a total length of 50 m) having a platewidth of 50 mm, a plate thickness of 0.15 mm, a blade edge width of 1.4mm, and a blade edge end thickness of 0.07 mm were appropriatelysubjected to a pre-treatment, and then a ceramic dispersednickel-phosphorus composite plating containing SiC particles (inComparative Example 7, a tetrafluoroethylene resin particle-containingnickel-phosphorus composite plating) was performed thereon. Thereafter,surface treatment was appropriately performed on the specimens tothereby prepare the surface treated doctor blades of Examples 36 to 64and Comparative Examples 7 and 8 as shown in Table 3. Table 3 shows theresults of the measurement and evaluation, as in Example 35, of theVickers hardness (Hv), layer thickness of each layer, surface energy ofthe second layer, property for continuous printing, ink scrapingproperty, and coating film adhesion of these surface treated doctorblades. Table 4 shows the average particle sizes of thetetrafluoroethylene resin particles (PTFE (1) to PTFE (6)) used.

EXAMPLE 65

Plating Process;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was continuously subjected toelectrolysis (Pakuna Erekuta J (manufactured by Yuken Industry Co.,Ltd.): 5 vol %, NaOH: 50 g/l, 30° C., 2.5 A) and washed in water.Thereafter, electric chromium plating (chromic anhydride: 250 g/l,H₂SO₄: 2.5 g/L, HEEF25C: 20 ml/l, bath temperature: 50° C.) wasperformed on the specimen, adjusting the plating current and platingtime so as to attain a predetermined plating thickness, to therebyprepare a single-layer chromium-plated blade 1.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layerchromium-plated blade 1 to completely remove the plating residues or thelike from the surface. After performing annealing at 300° C. for anhour, there was obtained a single-layer chromium-plated blade 2.

Coating Process;

An acrylic resin coating material containing tetrafluoroethylene resin(5) was applied to the single-layer chromium-plated blade 2 by using aroll coater such that the film thickness when dried was 1 μm, and thendried in a hot-air drying furnace. Thereafter, the specimen was shearedin a predetermined size to thereby obtain a blade having a double-layerstructure according to the present invention.

The Vickers hardness (Hv), layer thickness of each layer, surface energyof the second layer, property for continuous printing, ink scrapingproperty, and coating film adhesion of this surface treated doctor bladewere evaluated in the same manner as in Example 35. Table 3 shows theresults of measurement and evaluation.

COMPARATIVE EXAMPLE 9

Tetrafluoroethylene-based resin coating was applied to asingle-and-parallel-edged steel base material for doctor blade (a steelstrip having a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm by using a roll coater such that the filmthickness when dried was 7 μm, and then dried in a hot-air dryingfurnace. Thereafter, the specimen was sheared in a predetermined size.

The Vickers hardness (Hv), coating film thickness, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured and evaluated in thesame manner as in Example 35. Table 3 shows the results of measurementand evaluation. TABLE 3 Surface treated doctor blade and qualityperformance Second layer PTFE First layer resin Film particle thicknesscontent Film thickness Surface No. Type (A) Coating film type (vol %)(B) energy Example 35 Ni—P—SiC 6 Acrylic resin coating film containingPTFE(5) 30 1 Low 36 Ni—P—SiC 6 PTFE-based coating film — 1 Low 37Ni—P—SiC 6 Silicone resin-based coating film — 1 Low 38 Ni—P—SiC 6Perfluoroalkoxy resin-based coating film — 1 Low 39 Ni—P—SiC 6Fluorinated ethylene propylene resin-based coating film — 1 Low 40Ni—P—SiC 6 Acrylic resin-based coating film — 1 Low 41 Ni—P—SiC 6 Epoxyresin coating film containing PTFE(5) 30 1 Low 42 Ni—P—SiC 6 Acrylicresin coating film containing PTFE(2) 30 1 Low 43 Ni—P—SiC 6 Acrylicresin coating film containing PTFE(3) 30 1 Low 44 Ni—P—SiC 6 Acrylicresin coating film containing PTFE(4) 30 1 Low 45 Ni—P—SiC 6 Acrylicresin coating film containing PTFE(6) 30 1 Low 46 Ni—P—SiC 6 Acrylicresin coating film containing PTFE(7) 30 1 Low 47 Ni—P—SiC 6 PTFE-basedcoating film — 1 Low 48 Ni—P—SiC 6 PTFE-based coating film — 1 Low 49Ni—P—SiC 6 PTFE-based coating film — 1 Low 50 Ni—P—SiC 6 PTFE-basedcoating film — 1 Low 51 Ni—P—SiC 6 PTFE-based coating film — 1 Low 52Ni—P—SiC 6 PTFE-based coating film — 1 Low 53 Ni—P—SiC 1.6 PTFE-basedcoating film — 0.4 Low 54 Ni—P—SiC 3.3 PTFE-based coating film — 0.7 Low55 Ni—P—SiC 5 PTFE-based coating film — 1 Low Total Film Coating No.film thickness thickness ratio (B/A) Hardness (Hv) Continuous printingInk scraping property film adhesion Example 35 7 0.17 1000 ⊚ ⊚ ◯ 36 70.17 900 ⊚ ⊚ ◯ 37 7 0.17 1000 ◯ ⊚ ◯ 38 7 0.17 1000 ⊚ ⊚ ◯ 39 7 0.17 1000⊚ ⊚ ◯ 40 7 0.17 1000 ◯ ◯ ◯ 41 7 0.17 1000 ⊚ ◯ ◯ 42 7 0.17 1000 ◯ ⊚ Δ 437 0.17 1000 ◯ ⊚ ◯ 44 7 0.17 1000 ⊚ ⊚ ◯ 45 7 0.17 1000 ◯ ◯ ◯ 46 7 0.171000 Δ ◯ ◯ 47 7 0.17 600 Δ Δ ◯ 48 7 0.17 750 ⊚ ◯ ◯ 49 7 0.17 900 ⊚ ⊚ ◯50 7 0.17 1100 ⊚ ⊚ ◯ 51 7 0.17 1200 ◯ ⊚ ◯ 52 7 0.17 1400 Δ ◯ Δ 53 2 0.25700 Δ ◯ ◯ 54 4 0.21 900 ◯ ⊚ ◯ 55 6 0.20 1000 ⊚ ⊚ ◯ Second layer PTFEresin First layer particle Film Film thickness content thickness SurfaceNo. Type (A) (μm) Coating film type (vol %) (B) (μm) energy Example 56Ni—P—SiC 8 PTFE-based coating film — 2 Low 57 Ni—P—SiC 12 PTFE-basedcoating film — 2 Low 58 Ni—P—SiC 25 PTFE-based coating film — 4 Low 59Ni—P—SiC 7.9 PTFE-based coating film — 0.06 Low 60 Ni—P—SiC 7.6PTFE-based coating film — 0.4 Low 61 Ni—P—SiC 7.3 PTFE-based coatingfilm — 0.7 Low 62 Ni—P—SiC 6.2 PTFE-based coating film — 1.8 Low 63Ni—P—SiC 5 PTFE-based coating film — 3 Low 64 Ni—P—SiC 4 PTFE-basedcoating film — 4 Low 65 Cr 6 Acrylic resin coating film containing 30 1Low Comparative 5 Ni—P—SiC 7 — — — — Example 6 Ni—P*¹-PTFE(1) 8 — — — —7 Ni—P*¹-PTFE(1) 6 Arcylic resin coating film containing PTFE(5) 30 1Low 8 Ni—P—SiC 6 Epoxy resin coating film — 1 High (high surface energycoating film) 9 PTFE-based 7 — — — — coating film Total film thicknessFilm Coating No. (A + B) thickness ratio (B/A) Hardness (Hv) Continuousprinting Ink scraping property film adhesion Example 56 10 0.25 1000 ⊚ ⊚◯ 57 14 0.17 1000 ◯ ⊚ Δ 58 29 0.16 1000 Δ ◯ Δ 59 8 0.007 1100 ◯ Δ ◯ 60 80.05 1100 ◯ ◯ ◯ 61 8 0.10 1000 ⊚ ⊚ ◯ 62 8 0.30 1000 ⊚ ⊚ ◯ 63 8 0.60 900◯ ⊚ ◯ 64 8 1.00 700 ◯ ◯ ◯ 65 7 0.17 900 ◯ ⊚ ◯ Comparative 5 7 — 1000 Δ x◯ Example 6 8 — 700 x x ◯ 7 7 0.17 600 x x Δ 8 7 0.17 1000 x x ◯ 9 7 —600 x x Δ*¹PTFE content is 20 to 25 vol %

TABLE 4 Particle size of PTFE Particle size (μm) PTFE(1) 0.22 PTFE(2)0.06 PTFE(3) 0.12 PTFE(4) 0.17 PTFE(5) 0.7 PTFE(6) 5 PTFE(7) 7

EXAMPLE 66

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60 g/l)of 50° C. for 15 minutes. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 15 minutes and further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which SiC (3) particles of an average particle size of 0.5μm were dispersed (a plating solution manufactured by Japan Kanigen Co.,Ltd. (Sumer SC-80-1: 20 vol %, Sumer SC-80-4; 2 vol %) at 87° C. until apredetermined film thickness was attained to effect a nickel-phosphoruscomposite plating containing SiC. After being washed in water, thespecimen was dried. Thereafter, the spacer and the blade were unwoundand separated to thereby obtain a blade 1 plated with an SiCparticle-containing nickel-phosphorus-based composite (Ni—P—SiC(3))single layer plating.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Plating Process 2;

The single-layer-plated blade 2 was again spirally taken up on the reeltogether with the spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed for 5 minutes in an alkalidegreasing solution (Pakuna RT-T (manufactured by Yuken Industry Co.,Ltd.) 50 g/l) of 50° C. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution, and was further washed in water. Thereafter,the specimen was immersed in an electroless Ni plating solution in whichtetrafluoroethylene resin (1) (PTFE(1)) (average particle size: 0.22 μm)is dispersed (a plating solution manufactured by Japan Kanigen Co., Ltd.(Kaniflon-0: 20 vol %, Kaniflon-4A (a solution in whichtetrafluoroethylene resin (1) is dispersed): 2 vol %) at 86° C. until apredetermined film thickness was attained to effect an organic resindispersed nickel-phosphorus composite plating (Ni—P-PTFE(1)) containing20 to 25 vol % of tetrafluoroethylene resin (1), and then the specimenwas washed in water and dried. Thereafter, the spacer and the blade wereunwound and separated to obtain a double-layer-plated blade 1 having aNi—P—SiC (3) plating and a layer provided thereon and consisting of anickel-phosphorus-based composite plating layer in which PTFE (1) wasdispersed (Ni—P-PTFE (1)).

Post-Treatment Process;

Exclusively the blade edge end of the above double-layer-plated blade 1was polished with a abrasive paper of #2000 to remove the surfacetreatment coating exclusively from the blade edge end, whereby the bladebase material was completely exposed. Thereafter, annealing wasperformed thereon at 300° C. for an hour, and the specimen was shearedin a predetermined size. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured. Further, property for continuous printing, ink scrapingproperty, and coating film adhesion were evaluated in the same manner asin Example 1. Further, conformability of the blade edge end wasevaluated by the following evaluation criteria:

(1) Blade Edge End Conformability

With respect to a printing machine in which a blade according to Example66 was mounted, a running-in was conducted using an oil-based ink.Evaluation was made on the basis of the length of time immediately fromthe time when the operation started until the time when normal printingwithout involving any printing failure in printed product, such asstreaks, fogs, blurring, or bleeding started.

-   -   ⊚: less than five minutes    -   ◯: not less than five minutes and less than 30 minutes    -   Δ: not less than 30 minutes and less than 60 minutes    -   X: not less than 60 minutes

Table 5 collectively shows the measurement and evaluation resultsregarding the thickness (A) of the first layer, thickness (B) of thesecond layer, the amount of tetrafluoroethylene resin (PTFE) containedin the second layer, surface energy of the second layer, total thickness(A+B), thickness ratio (B/A), surface hardness (Hv), property forcontinuous printing, ink scraping property, coating film adhesion, andblade edge end conformability of this surface treated doctor blade.

EXAMPLES 67 to 101

Plating Process;

As in Example 66, an appropriate pre-treatment was performed on asingle-and-parallel-edged steel base material for doctor blade (a steelstrip with a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm, and then the base material was immersedin an electroless Ni plating solution in which various types of SiC (SiC(1) to SiC (5)) with the average particle sizes as shown in Table 7 weredispersed, at 87° C. until a predetermined film thickness was attainedto thereby effect an SiC containing nickel-phosphorus composite plating(Ni—P—SiC (1) to (5)). After being washed in water, the specimen wasimmersed in an electroless Ni plating solution in which various types oftetrafluoroethylene resin (PTFE (1) to (8)) with the average particlesizes as shown in Table 6 were dispersed, at 86° C. until apredetermined film thickness was attained to thereby effect anickel-phosphorus composite plating containing the tetrafluoroethyleneresin ((Ni—P-PTFE (1) to (8)). After being washed in water, the specimenwas dried. Thereafter, the spacer and the blade were unwound andseparated, and then a double-layer-plated blade 1 was obtained.

Post-Treatment Process;

Exclusively the blade edge end of the above double-layer-plated blade 1was polished with a abrasive paper of #2000 to remove the surfacetreatment coating exclusively from the blade edge end, where the bladebase material was completely exposed. Thereafter, annealing wasperformed thereon at 300° C. for an hour, and the specimen was shearedin a predetermined size. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured. Further, conformability of the blade edge end, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured and evaluated in thesame manner as in Example 66. Table 5 shows the measurement andevaluation results.

EXAMPLES 102 to 106

Plating Process 1;

As in Example 66, an appropriate pre-treatment was performed on asingle-and-parallel-edged steel base material for doctor blade (a steelstrip with a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm, and then the base material was immersedin an electroless Ni plating solution in which SiC (3) particles weredispersed (plating solution manufactured by Japan Kanigen Co., Ltd.;Sumer SC-80-1: 20 vol %, Sumer SC-80-4: 2 vol %), at 87° C. until apredetermined film thickness was attained to thereby effect aceramic-dispersed nickel-phosphorus composite plating containing SiC(Ni—P—SiC (3)). After being washed in water, the specimen was dried.Thereafter, the spacer and the blade were unwound and separated, andthen a single-layer-plated blade 1 was obtained.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface. After performing annealing at 300° C. for an hour, there wasobtained a single-layer-plated blade 2.

Coating Process;

A resin coating material containing the resin as shown in Table 5 wasapplied to the single-layer-plated blade 2 by using a roll coater suchthat the film thickness when dried was 1 μm, and then dried in a hot-airdrying furnace, thereby obtaining a double-layer-treated blade.

Post-Treatment Process;

Exclusively the blade edge end of the above double-layer-treated bladewas polished with a abrasive paper of #2000 to remove the surfacetreatment coating exclusively from the blade edge end, where the bladebase material was completely exposed. Thereafter, the specimen wassheared in a predetermined size. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured.

Further, conformability of the blade edge end, property for continuousprinting, ink scraping property, and coating film adhesion of thissurface treated doctor blade were measured and evaluated in the samemanner as in Example 66. Table 5 shows the measurement and evaluationresults.

EXAMPLE 107

Plating Process 1;

As in Example 66, an appropriate pre-treatment was performed on asingle-and-parallel-edged steel base material for doctor blade (a steelstrip with a total length of 50 m) having a plate width of 50 mm, aplate thickness of 0.15 mm, a blade edge width of 1.4 mm, and a bladeedge end thickness of 0.07 mm, and then the base material was immersedin an electroless Ni plating solution in which boron nitride (BN) wasdispersed, at 87° C. until a predetermined film thickness was attainedto thereby effect nickel-phosphorus composite plating containing boronnitride (BN) (Ni—P—BN). After being washed in water, the specimen wasdried. Thereafter, the spacer and the blade were unwound and separated,and then a single-layer-plated blade 1 was obtained.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Plating Process 2;

The single-layer-plated blade 2 was subjected to the pre-treatmentdescribed in Plating process 2 of Example 66, and was immersed in anelectroless Ni plating solution in which a tetrafluoroethylene resin (1)(PTFE(1)) (average particle size: 0.22 μm) was dispersed (a platingsolution manufactured by Japan Kanigen Co., Ltd. (Kaniflon-0: 20 vol %,Kaniflon-4A (a solution in which tetrafluoroethylene resin (1) wasdispersed): 2 vol %) at 86° C. until a predetermined film thickness wasattained to effect an organic resin dispersed nickel-phosphoruscomposite plating (Ni—P-PTFE(1)) containing 20 to 25 vol % oftetrafluoroethylene resin (1), and then the specimen was washed in waterand dried. Thereafter, the spacer and the blade were unwound andseparated to obtain a double-layer-plated blade 1.

Post-Treatment Process;

Exclusively the blade edge end of the above double-layer-plated blade 1was polished with a abrasive paper of #2000 to remove the surfacetreatment coating film exclusively from the blade edge end, where theblade base material was completely exposed. Thereafter, annealing wasperformed thereon at 300° C. for an hour, and the specimen was shearedin a predetermined size. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured. Further, conformability of the blade edge end, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured and evaluated in thesame manner as in Example 66. Table 5 shows results thereof.

EXAMPLE 108

A surface-treated blade with its base material exposed exclusively atthe blade edge end by removing the surface treatment coating wasprepared through the same manner as that in Example 66, except thatplating which contained no ceramic was given as the first layer. Thesurface hardness (Hv), coating film thickness, and surface energy ofthis surface treated doctor blade were measured. Further, conformabilityof the blade edge end, property for continuous printing, ink scrapingproperty, and coating film adhesion of this surface treated doctor bladewere measured and evaluated in the same manner as in Example 66. Table 5shows the measurement and evaluation results.

COMPARATIVE EXAMPLE 10

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60 g/L)of 50° C. for 15 minutes. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 15 minutes and further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which SiC (3) was dispersed (a plating solution manufacturedby Japan Kanigen Co., Ltd. (SC-80-1: 20 vol %, SC-80-4: 2 vol %) at 87°C. until a predetermined film thickness was attained to effect anickel-phosphorus composite plating containing SiC (3) (Ni—P—Sic (3)).After being washed in water, the specimen was dried. Thereafter, thespacer and the blade were unwound and separated to thereby obtain asingle-layer-plated blade 1.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Post-Treatment Process;

Exclusively the blade edge end of the above single-layer-plated blade 2was polished with a abrasive paper of #2000 to remove the surfacetreatment coating film exclusively from the blade edge end, where theblade base material was completely exposed. Thereafter, annealing wasperformed thereon at 300° C. for an hour, and the specimen was shearedin a predetermined size. The surface hardness (Hv) and coating filmthickness of this surface treated doctor blade were measured. Further,conformability of the blade edge end, property for continuous printing,ink scraping property, and coating film adhesion of this surface treateddoctor blade were measured and evaluated in the same manner as inExample 66. Table 5 shows the results thereof.

COMPARATIVE EXAMPLE 11

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60 g/L)of 50° C. for 15 minutes. After being washed in water, the specimen wassubjected to hydrochloric acid activation treatment in a hydrochloricacid activation solution for 15 minutes to be further washed in water.Thereafter, the specimen was immersed in an electroless Ni platingsolution in which a tetrafluoroethylene resin (1) (PTFE(1)) wasdispersed (a plating solution manufactured by Japan Kanigen Co., Ltd.((Kaniflon-0: 20 vol %, Kaniflon-4A (a solution in which thetetrafluoroethylene resin (1) is dispersed): 2 vol %) at 86° C. until apredetermined coating film thickness was attained to effect anickel-phosphorus composite plating (Ni—P-PTFE(1))containing 20 to 25vol % of tetrafluoroethylene resin (1). After being washed in water, thespecimen was dried. Thereafter, the spacer and the blade were unwoundand separated to thereby obtain a single-layer-plated blade 1.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a signle-layer-plated blade 2.

Post-Treatment Process;

Exclusively the blade edge end portion of the above single-layer-platedblade 2 was polished with a abrasive paper of #2000 to remove thesurface treatment coating film exclusively from the blade edge end,where the blade base material was completely exposed. Thereafter,annealing was performed thereon at 300° C. for an hour, and the specimenwas sheared in a predetermined size. The surface hardness (Hv) andcoating film thickness of this surface treated doctor blade weremeasured. Further, conformability of the blade edge end, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured and evaluated in thesame manner as in Example 66. Table 5 shows the results thereof.

COMPARATIVE EXAMPLE 12

A surface treated blade having a treatment coating also, at the bladeedge end was produced through the same process as in Comparative Example10 except that the step of polishing the blade edge end with a #2000abrasive paper was omitted. The surface hardness (Hv) and coating filmthickness of this surface treated doctor blade were measured. Further,conformability of the blade edge end, property for continuous printing,ink scraping property, and coating film adhesion of this surface treateddoctor blade were measured and evaluated in the same manner as inExample 66. Table 5 shows the results thereof.

COMPARATIVE EXAMPLE 13

A surface treated blade having a treatment coating also at the bladeedge end was produced through the same process as in Comparative Example11 except that the step of polishing the blade edge end with a #2000abrasive paper was omitted. The surface hardness (Hv) and coating filmthickness of this surface treated doctor blade were measured, andconformability of the blade edge end, property for continuous printing,ink scraping property, and coating film adhesion of this surface treateddoctor blade were measured and evaluated in the same manner as inExample 66. Table 5 shows the measurement and evaluation results.

COMPARATIVE EXAMPLE 14

Plating Process 1;

A single-and-parallel-edged steel base material for doctor blade (asteel strip having a total length of 50 m) having a plate width of 50mm, a plate thickness of 0.15 mm, a blade edge width of 1.4 mm, and ablade edge end thickness of 0.07 mm was spirally taken up on a reeltogether with a spacer consisting of a metal steel strip which had thesurface roughened by embossing treatment, and in the state in which itwas wound around the reel, it was immersed in an alkali degreasingsolution (Pakuna RT-T (manufactured by Yuken Industry Co., Ltd.) 60g/liter) of 50° C. for 15 minutes. After being washed in water, thespecimen was subjected to hydrochloric acid activation treatment in ahydrochloric acid activation solution for 15 minutes, and further washedin water. Thereafter, the specimen was immersed in an electroless Niplating solution in which a tetrafluoroethylene resin (1) (PTFE(1)) wasdispersed (a plating solution manufactured by Japan Kanigen Co., Ltd.((Kaniflon-0: 20 vol %, Kaniflon-4A (a solution in whichtetrafluoroethylene resin (1) was dispersed): 2 vol %) at 86° C. until apredetermined film thickness was attained to effect a nickel-phosphoruscomposite plating (Ni—P-PTFE (1)) containing 20 to 25 vol % oftetrafluoroethylene resin (1). After being washed in water, the specimenwas dried. Thereafter, the spacer and the blade were unwound andseparated to thereby obtain a single-layer-plated blade 1.

Surface Adjustment Process;

Buff polishing was performed on the above-mentioned single-layer-platedblade 1 to completely remove the plating residues or the like from thesurface, thereby obtaining a single-layer-plated blade 2.

Plating Process 2;

Further, in the same manner as in Plating process 1 of Example 66, therewas effected a nickel-phosphorus composite plating (Ni—P—SiC (3))containing SiC (3). After being washed in water, the specimen was dried.Thereafter, the spacer and the blade were unwound and separated tothereby obtain a double-layer-plated blade 1.

Post-Treatment Process;

Exclusively the blade edge end of the above double-layer-plated blade 1was polished with a abrasive paper of #2000 to remove the surfacetreatment coating film exclusively from the blade edge end, where theblade base material was completely exposed. Thereafter, annealing wasperformed thereon at 300° C. for an hour, and the specimen was shearedin a predetermined size. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured. Further, conformability of the blade edge end, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured evaluated in the samemanner as in Example 66. Table 5 shows the results thereof.

COMPARATIVE EXAMPLE 15

The same treatment as that in Example 66, except a nickel-phosphorusalloy plating (Ni—P) containing no fluorine-based resin, was performedto provide a second layer. The surface hardness (Hv), coating filmthickness, and surface energy of this surface treated doctor blade weremeasured. Further, conformability of the blade edge end, property forcontinuous printing, ink scraping property, and coating film adhesion ofthis surface treated doctor blade were measured and evaluated in thesame manner as in Example 66. Table 5 shows the results thereof.

COMPARATIVE EXAMPLE 16

As in Example 66, an SiC particle-containing nickel-phosphorus-basedcomposite plating (Ni—P—SiC (3)) was performed to provide a first layer,and annealing was conducted at 300° C. for an hour. Thereafter, an epoxyresin coating material was applied as a second layer. After baking thecoating layer, the specimen was sheared in a predetermined size. Thesurface hardness (Hv), coating film thickness, and surface energy ofthis surface treated doctor blade were measured. Further, conformabilityof the blade edge end, property for continuous printing, ink scrapingproperty, and coating film adhesion of this surface treated doctor bladewere measured and evaluated in the same manner as in Example 66. Table 5shows the measurement and evaluation results. TABLE 5 Surface treateddoctor blade and quality performance base First layer Second layermaterial of Film PTFE blade edge thickness content Film thicknessSurface Total film No. end Type (A) (μm) Type (vol %) (B) (μm) energythickness (A +B) Example 66 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 20 to 251 Low 7 67 Exposed Ni—P—SiC(3) 7 Ni—P-PTFE(1) 20 to 25 1 Low 8 68Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 3 to 7 1 Low 7 69 Exposed Ni—P—SiC(3)6 Ni—P-PTFE(1) 10 to 15 1 Low 7 70 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 30to 35 1 Low 7 71 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 45 to 50 1 Low 7 72Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(2) 20 to 25 1 Low 7 73 ExposedNi—P—SiC(3) 6 Ni—P-PTFE(3) 20 to 25 1 Low 7 74 Exposed Ni—P—SiC(3) 6Ni—P-PTFE(4) 20 to 25 1 Low 7 75 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(5) 20to 25 1 Low 7 76 Exposed Ni—P—SiC(3) 7 Ni—P-PTFE(6) 20 to 25 2 Low 9 77Exposed Ni—P—SiC(3) 7 Ni—P-PTFE(7) 20 to 25 2 Low 9 78 ExposedNi—P—SiC(3) 7 Ni—P-PTFE(8) 20 to 25 2 Low 9 79 Exposed Ni—P—SiC(3) 6Ni—P-PTFE(1) 20 to 25 1 Low 7 80 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 20to 25 1 Low 7 81 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 20 to 25 1 Low 7 82Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 20 to 25 1 Low 7 83 ExposedNi—P—SiC(3) 6 Ni—P-PTFE(1) 20 to 25 1 Low 7 84 Exposed Ni—P—SiC(3) 6Ni—P-PTFE(1) 20 to 25 1 Low 7 85 Exposed Ni—P—SiC(3) 6 Ni—P-PTFE(1) 20to 25 1 Low 7 86 Exposed Ni—P—SiC(3) 2.1 Ni—P-PTFE(4) 20 to 25 0.4 Low2.5 87 Exposed Ni—P—SiC(3) 3.3 Ni—P-PTFE(1) 20 to 25 0.7 Low 4 88Exposed Ni—P—SiC(3) 5 Ni—P-PTFE(1) 20 to 25 1 Low 6 89 ExposedNi—P—SiC(3) 10 Ni—P-PTFE(1) 20 to 25 2 Low 12 90 Exposed Ni—P—SiC(3) 16Ni—P-PTFE(1) 20 to 25 4 Low 20 91 Exposed Ni—P—SiC(3) 21 Ni—P-PTFE(1) 20to 25 4 Low 25 92 Exposed Ni—P—SiC(3) 7.7 Ni—P-PTFE(4) 20 to 25 0.3 Low8 93 Exposed Ni—P—SiC(3) 7.5 Ni—P-PTFE(1) 20 to 25 0.5 Low 8 94 ExposedNi—P—SiC(3) 7.1 Ni—P-PTFE(1) 20 to 25 0.9 Low 8 95 Exposed Ni—P—SiC(3)6.2 Ni—P-PTFE(1) 20 to 25 1.8 Low 8 96 Exposed Ni—P—SiC(3) 5.3Ni—P-PTFE(1) 20 to 25 2.7 Low 8 97 Exposed Ni—P—SiC(3) 3.6 Ni—P-PTFE(1)20 to 25 4.4 Low 8 98 Exposed Ni—P—SiC(1) 6 Ni—P-PTFE(1) 20 to 25 1 Low7 99 Exposed Ni—P—SiC(2) 6 Ni—P-PTFE(1) 20 to 25 1 Low 7 100 ExposedNi—P—SiC(4) 6 Ni—P-PTFE(1) 20 to 25 1 Low 7 101 Exposed Ni—P—SiC(5) 6Ni—P-PTFE(1) 20 to 25 1 Low 7 102 Exposed Ni—P—SiC(3) 7 Acrylic resin 20to 25 1 Low 8 containing PTFE(5) 103 Exposed Ni—P—SiC(3) 7Silicone-based — 1 Low 8 resin 104 Exposed Ni—P—SiC(3) 7 PTFE resin — 1Low 8 105 Exposed Ni—P—SiC(3) 7 Perfluoroalkoxy- — 1 Low 8 based resin106 Exposed Ni—P—SiC(3) 7 Fluorinated — 1 Low 8 ethylene propylene-basedresin 107 Exposed Ni—P-BN 7 Ni—P-PTFE(1) 20 to 25 1 Low 8 108 ExposedNi—P 7 Ni—P-PTFE(1) 20 to 25 1 Low 8 Comparative 10 Exposed Ni—P—SiC(3)7 — — — — 7 Example 11 Exposed Ni—P- 7 — — — — 7 PTFE(1)*¹ 12 Notexposed Ni—P—SiC(3) 7 — — — — 7 13 Not exposed Ni—P- 7 — — — — 7PTFE(1)*¹ 14 Exposed Ni—P- 6 Ni—P—SiC(3) — 1 High 7 PTFE(1)*¹ 15 ExposedNi—P—SiC(3) 6 Ni—P 0 1 High 7 16 Exposed Ni—P—SiC(3) 7 Epoxy resin — 1High 8 Continuous Film thickness Blade tip printing Ink scraping Coatingfilm No. ratio (B/A) Hardness (Hv) conformability characteristicproperty adhesion Example 66 0.17 1000 ⊚ ⊚ ⊚ ◯ 67 0.14 1000 ⊚ ⊚ ⊚ ◯ 680.17 1000 ◯ ◯ ◯ ◯ 69 0.17 1000 ⊚ ⊚ ◯ ◯ 70 0.17 1000 ⊚ ◯ ⊚ ◯ 71 0.17 1000⊚ ◯ ◯ Δ 72 0.17 1000 ⊚ Δ ⊚ Δ 73 0.17 1000 ⊚ ◯ ⊚ ◯ 74 0.17 1000 ⊚ ⊚ ⊚ ◯75 0.17 1000 ⊚ ⊚ ⊚ ◯ 76 0.29 1000 ⊚ ⊚ ◯ ◯ 77 0.29 1000 ⊚ ◯ ◯ ◯ 78 0.291000 ⊚ Δ ◯ Δ 79 0.17 500 ⊚ Δ ◯ ◯ 80 0.17 750 ⊚ ◯ ⊚ ◯ 81 0.17 850 ⊚ ⊚ ⊚ ◯82 0.17 900 ⊚ ⊚ ⊚ ◯ 83 0.17 1100 ⊚ ⊚ ⊚ ◯ 84 0.17 1200 ⊚ ◯ ⊚ ◯ 85 0.171350 ⊚ Δ ◯ Δ 86 0.19 720 ⊚ Δ ◯ ◯ 87 0.21 900 ⊚ ◯ ⊚ ◯ 88 0.20 1000 ⊚ ⊚ ⊚◯ 89 0.20 1000 ⊚ ◯ ⊚ ◯ 90 0.25 1000 ⊚ ◯ ⊚ Δ 91 0.19 1000 ⊚ Δ ◯ Δ 92 0.041100 ⊚ ◯ Δ ◯ 93 0.07 1100 ⊚ ⊚ ◯ ◯ 94 0.12 1000 ⊚ ⊚ ⊚ ◯ 95 0.29 1000 ⊚ ⊚⊚ ◯ 96 0.50 900 ⊚ ◯ ⊚ ◯ 97 1.22 750 ⊚ Δ ◯ ◯ 98 0.17 800 ⊚ ◯ ◯ ◯ 99 0.17900 ⊚ ⊚ ◯ ◯ 100 0.17 1000 ⊚ ◯ ⊚ ◯ 101 0.17 1000 ⊚ Δ ◯ Δ 102 0.14 1000 ⊚⊚ ⊚ ◯ 103 0.14 1000 ⊚ ◯ ◯ ◯ 104 0.14 1000 ⊚ ⊚ ⊚ ◯ 105 0.14 1000 ⊚ ⊚ ◯ ◯106 0.14 1000 ⊚ ⊚ ◯ ◯ 107 0.14 1000 ⊚ ◯ ⊚ Δ 108 0.17 750 ⊚ Δ ◯ ◯Comparative 10 — 1000 ◯ Δ X ◯ Example 11 — 500 ◯ X X ◯ 12 — 1000 X Δ X ◯13 — 600 X X X ◯ 14 0.17 900 Δ X X X 15 0.17 900 Δ Δ X ◯ 16 0.14 1000 ΔΔ X ◯*¹PTFE content is 20 to 25 vol %

TABLE 6 Particle size of PTFE Particle size (υm) PTFE(1) 0.22 PTFE(2)0.06 PTFE(3) 0.12 PTFE(4) 0.16 PTFE(5) 0.35 PTFE(6) 0.7 PTFE(7) 1.5PTFE(8) 6

TABLE 7 Particle size of SiC particle Particle size(μm) SiC(1) 0.07SiC(2) 0.1 SiC(3) 0.5 SiC(4) 1.5 SiC(5) 3

INDUSTRIAL APPLICABILITY

In the surface treated doctor blade of the present invention, which hasa first layer consisting of a nickel-based plating or a chromium-basedplating and a second layer provided thereon and having low surfaceenergy, an improvement is achieved in terms of wear resistance of theblade edge end, thereby restraining generation of printing failuresduring continuous printing. In the mode in which at least a part of theblade base material is exposed, it is possible to reduce running-in timefor adjustment of contact of the blade edge with the cylinder. Inaccordance with the present invention, it is possible to produce adoctor blade with the above properties with low cost.

1. A surface treated doctor blade, wherein a surface of at least theblade edge portion of base material comprises a first layer consistingof a nickel-based plating or a chromium-based plating (exclusive of anorganic resin dispersed composite plating in which organic resinparticles are dispersed) and a second layer provided thereon which haslow surface energy.
 2. The surface treated doctor blade as claimed inclaim 1, wherein the plating of the first layer is anickel-phosphorus-based composite plating containing ceramic particles.3. The surface treated doctor blade as claimed in claim 2, wherein theparticle size of the ceramic particles is 0.05 to 10 μm.
 4. The surfacetreated doctor blade as claimed in claim 2, wherein the ceramicparticles are SiC particles.
 5. The surface treated doctor blade asclaimed in claim 1, wherein the second layer is a layer consisting of anorganic resin dispersed composite plating containing fluorine-basedresin particles.
 6. The surface treated doctor blade as claimed in claim5, wherein the type of the fluorine-based resin particles is at leastone type of particle selected from a group consisting oftetrafluoroethyelene-based resin, perfluoroalkoxy-based resin, andfluorinated ethylene propylene-based resin.
 7. The surface treateddoctor blade as claimed in claim 6, wherein the particle size of thefluorine-based resin particles is 0.05 to 10 μm.
 8. The surface treateddoctor blade as claimed in claim 7, wherein the particle size of thefluorine-based resin particles is not more than 1.2 times the platingthickness of the second layer.
 9. The surface treated doctor blade asclaimed in claim 1, wherein the second layer consists of an organicresin coating film layer having low surface energy.
 10. The surfacetreated doctor blade as claimed in claim 9, wherein the organic resincoating film is at least one type of organic resin coating film selectedfrom silicone-based resin, fluorine-based resin, and an organic resincontaining particles of silicone-based resin and/or fluorine-basedresin.
 11. The surface treated doctor blade as claimed in claim 9,wherein the organic resin coating film is at least one type of organicresin coating film selected from a group consisting oftetrafluoroethylene-based resin, perfluoroalkoxy-based resin,fluorinated ethylene propylene-based resin, and an organic resincontaining these resins in the form of particles.
 12. The surfacetreated doctor blade as claimed in claim 1, wherein blade base materialof the blade edge end portion is exposed at least in a part.
 13. Thesurface treated doctor blade as claimed in claim 1, wherein Vickershardness (Hv) of the doctor blade is within a range of 400 to
 1500. 14.The surface treated doctor blade as claimed in claim 1, wherein the sumtotal of a film thickness (A) of the first layer and a film thickness(B) of the second layer is within a range of 2 μm to 30 μm.
 15. Asurface treated doctor blade as claimed in claim 14, wherein the ratio(B/A) of the film thickness (B) of the second layer to the filmthickness (A) of the first layer is within a range of 0.005 to 1.3.